KR102119181B1 - Terminal apparatus and method for handoff of near-range wireless access - Google Patents

Abstract

The present invention relates to a terminal device and a short-range wireless access handoff method. The disclosed short-range wireless access handoff method includes scanning all channels for a wireless connection with an access point supporting a WLAN service, storing channel history information including information on a serviceable channel among all channels, and servicing Wireless access to an access point supporting a wireless LAN service through one of the available channels, determining whether a channel state of the access point wirelessly connected satisfies a handoff condition, and determining that the handoff condition is satisfied, Performing a channel scan for some channels based on channel history information among channels, and wirelessly accessing an access point supporting a wireless LAN service through one channel among some channels according to the result of the channel scan for some channels And performing a handoff to access. Therefore, when changing a channel of a short-range wireless connection for a wireless LAN service, all channels in all bands are not scanned, thereby saving unnecessary channel scan time, and as a result, it is possible to speed up the connection at the time of handoff. Whenever a handoff or handoff condition is satisfied, a faster connection can be made than before, and there is an advantage of using a smooth wireless LAN communication.

Description

TERMINAL APPARATUS AND METHOD FOR HANDOFF OF NEAR-RANGE WIRELESS ACCESS}

The present invention relates to a terminal device and its short-range wireless access handoff method, and more particularly, to a method for processing a handoff (handoff) in a short-range wireless connection for a wireless LAN service and a terminal device performing the same.

As is well known, a wireless local access network (WLAN) technology, unlike a conventional local access network (LAN), which connects and communicates terminal devices using a cable, without a cable between terminal devices at a certain distance. Wi-Fi, which is an abbreviation for wireless fidelity, is a network technology that can transmit and receive data. It is an alias for wireless LAN, and is built to mean that a wireless network can be conveniently used like hi-fi audio.

According to the wireless LAN service, a terminal device such as a smart phone, a PDA (Personal Digital Assistant), a tablet PC, or a notebook computer can use the wireless Internet within a certain distance centering on a place where an access point, which is a wireless access device, is installed.

In particular, with the popularization of mobile communication terminals and portable terminals, wireless LANs having potential as open wireless networks are rapidly expanding, and these wireless LANs are used to provide high-speed data services to cities, schools, airports, hotels, etc. throughout the city. have.

Accordingly, a mobile communication terminal including a wireless LAN module in addition to the mobile communication module has been developed so that a wireless LAN service can be provided in a mobile communication terminal, and a user can perform wireless LAN communication through a mobile communication terminal including the wireless LAN module. In the wireless LAN zone, wireless LAN service can be used. Such an area where wireless Internet is available is called a hot spot or a home zone.

This wireless LAN service is a protocol that eliminates the need for extensive cabling and router resets caused by information and communication (IT) activities in the company, such as moving, adding, or changing daily routines. It is evolving as the main connection method that can be done.

However, since the wireless LAN service uses wireless data communication in an unlicensed band, a terminal device such as a mobile communication terminal wirelessly switches to a channel of another wireless access device or another channel of the same wireless access device during communication using the wireless Internet. There was a problem in the handoff processing.

According to the short-range wireless access handoff method of a terminal device according to the prior art, the strength of the received signal strength indicator (RSSI) is weakened or the connection is unstable due to a reason, for example, that the terminal device moves away from an access point currently connected in a wireless LAN environment. When it is released, it is determined whether the preset handoff condition is satisfied, and when the handoff condition such as the RSSI strength reaches a threshold or a beacon message is not received, the terminal device hands to another frequency band or another access point of the same access point. Scan the surrounding channels to turn it off.

Here, the terminal device determines whether an access point that satisfies a handoff condition, such as whether the RSSI strength is greater than or equal to a certain reference, among serviceable channels after scanning all channels supported in the surrounding wireless environment and satisfies the handoff condition When there are multiple access points, handoff is performed to access one access point according to a predefined criterion.

However, when the number of supported channels in the wireless environment is large at the time when the terminal device is handed off, the access time is unnecessarily used to scan the bands of all channels and attempt to access the access point that satisfies the handoff condition. There was a problem that takes a lot.

For example, if there are multiple access points in the vicinity, and in the case of dual band supporting both 2.4GHz and 5GHz, there are 13 channels in 2.4GHz and 19 channels in 5GHz, so all channels in each band It takes a long time to scan. As described above, there is a problem that it takes more time than necessary to scan all the channels of each band, which is an obstacle to smooth handoff processing.

Republic of Korea Patent Publication No. 10-2009-0011484, published date 02/02/2009.

The present invention has been proposed to solve the problems of the prior art as described above, and when performing handoff, based on the result of channel scan for some channels based on the channel history information for the serviceable channels previously stored Provided is a short-range wireless access handoff method capable of performing handoff through one of the channels and a terminal device performing the same.

The problem to be solved of the present invention is not limited to those mentioned above, and another problem to be solved that is not mentioned will be clearly understood by those having ordinary knowledge to which the present invention belongs from the following description.

A short-range wireless access handoff method according to an aspect of the present invention comprises: scanning an entire channel for a wireless connection with an access point supporting a wireless LAN service; Storing channel description information including information on a serviceable channel among the entire channels; Wirelessly accessing an access point supporting the WLAN service through one of the serviceable channels; Determining whether a channel state of the wirelessly connected access point satisfies a handoff condition; If it is determined that the handoff condition is satisfied, performing a channel scan on some channels based on the channel description information among the entire channels; And performing a handoff to wirelessly access an access point supporting the WLAN service through one of the channels according to a result of a channel scan for the some channels.

A terminal device according to another aspect of the present invention includes: a wireless communication unit wirelessly accessing an access point supporting a wireless LAN service through a serviceable channel among all channels; A channel scanning unit that scans a channel for wireless access with an access point supporting the WLAN service; A channel information storage unit in which channel history information including information on a serviceable channel among all channels is stored; If the channel state of the wirelessly accessed access point satisfies the handoff condition, the wireless LAN service is performed through one channel among the partial channels according to a result of a channel scan targeting some channels based on the channel description information among the entire channels. It may include a wireless access control unit for processing a handoff for wireless access to an access point that supports.

According to an embodiment of the present invention, when performing handoff, handoff is performed through one channel of some channels according to a result of a channel scan targeting some channels based on channel history information for a service channel previously stored. can do.

Therefore, since all channels of all bands are not scanned, unnecessary channel scan time is saved, and as a result, connection can be quickly performed during handoff.

In addition, since the user can connect faster than the existing whenever the handoff condition is satisfied, there is an effect of using a smooth wireless LAN communication.

1 is a block diagram of a terminal device capable of performing a short-range wireless access handoff method according to an embodiment of the present invention.
2 is a flowchart illustrating a short-range wireless access handoff method according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the person having the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing embodiments of the present invention, when it is determined that a detailed description of known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the contents throughout this specification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a block diagram of a terminal device capable of performing a short-range wireless access handoff method according to an embodiment of the present invention.

As shown in this, the terminal device 100 according to the embodiment includes a wireless communication unit 110, a microphone 120, a camera module unit 130, a user input unit 140, an output unit 150, a memory unit 160, It includes an interface unit 170, a control unit 180, and the like. For example, the terminal device 100 may be implemented as various terminal devices capable of communication, such as a smart phone, a tablet computer, a notebook computer, and personal digital assistants (PDAs).

The wireless communication unit 110 includes a mobile communication unit 111, a local area communication unit 112, a GPS (Global Position System) receiving unit 113, and the like.

The mobile communication unit 111 transmits and receives wireless signals to and from at least one of a base station and an external terminal or server on a mobile communication network. Here, the wireless signal may include various types of data such as a voice call signal, a video call signal, or a text/multimedia message.

The short-range communication unit 112 transmits and receives wireless signals for short-range communication. For example, short-range communication may include Wi-Fi, Bluetooth, Radio Frequency Identification (RFID), infrared data association (IrDA), Ultra Wideband (UWB), ZigBee, and the like. . For example, the short-range communication unit 112 communicates a wireless signal including a beacon message to a Wi-Fi access point, and wirelessly accesses the access point through a serviceable channel among all channels for a WLAN service.

Here, the Wi-Fi access point is disposed in the wireless LAN zone, provides a connection function between the terminal device 100 receiving the wireless LAN service and the wired LAN, and can periodically broadcast a beacon message.

The GPS receiver 113 receives location information from a plurality of GPS satellites.

The microphone 120 receives an audio signal. The microphone 120 receives an external sound signal in a call mode, a recording mode, a voice recognition mode, etc., and processes it as electrical voice data. Then, the processed voice data may be converted into a form transmittable to a mobile communication base station through the mobile communication unit 111 and output.

The camera module unit 130 includes a rear camera 131 and a front camera 132. The camera module unit 130 receives a video signal under the control of the controller 180. The rear camera 131 is installed on the rear of the terminal device 100, and the front camera 132 is installed on the front of the terminal device 100. Among them, the front camera 132 is mainly used for video calls and self-portraits. The rear camera 131 and the front camera 132 process image frames such as still images or videos obtained by an image sensor in a video call mode or a shooting mode. In addition, the processed image frame may be displayed on the display unit 151.

The user input unit 140 generates key input data that the user inputs for controlling the operation of the terminal device 100. The user input unit 140 includes a key pad, a dome switch, and a touch pad (static pressure/power outage) that can receive commands or information by a user's push or touch operation. In particular, the touch pad forms a mutual layer structure with the display unit 151, which is called a touch screen. For example, the terminal device 100 may be a mobile communication terminal device including a touch screen as a type of input/output interface.

The output unit 150 includes a display unit 151 and an audio output unit 152, and outputs various signals such as an audio signal and a video signal.

The display unit 151 displays information processed by the terminal device 100. For example, when the terminal device 100 is in a call mode, a UI (User Interface) or a GUI (Graphic User Interface) related to the call is displayed. In addition, when the terminal device 100 is in a video call mode or a shooting mode, the captured or received video may be displayed respectively or simultaneously.

On the other hand, as described above, when the display unit 151 and the touch pad are configured as a touch screen by forming a mutual layer structure, the display unit 151 is also an input device capable of inputting information by a user's touch in addition to the output device. Can be used.

The audio output unit 152 outputs audio data received from the wireless communication unit 110 or stored in the memory unit 160 in a standby mode, a call mode, a recording mode, a voice recognition mode, a broadcast reception mode, or the like. In addition, the sound output unit 152 outputs sound signals related to a call signal reception sound, a message reception sound, etc. performed by the terminal device 100.

An operating system program 161 is stored in the memory unit 160, and the controller 180 can boot the terminal device 100 by executing the operating system program 161. Also, the memory unit 160 is a channel information storage unit 162 in which channel history information including information about a serviceable channel among all channels is stored according to a channel scan result by the local area communication unit 112 of the wireless communication unit 110. ).

The memory unit 160 includes a flash memory type, a hard disk type, a multimedia card micro type, and a card type memory (for example, SD or XD memory). , RAM, and ROM, may include at least one type of storage medium.

The interface unit 170 serves as an interface with all external devices connected to the terminal device 100. Examples of external devices connected to the terminal device 100 include a wired/wireless headset, an external charger, a wired/wireless data port, a card socket such as a memory card, a SIM (Subscriber Identification Module) card, and audio I/ There are O(Input/Output) terminal, video I/O(Input/Output) terminal, and earphone.

The control unit 180 includes a channel scan unit 181, a radio access control unit 182, and the like. The control unit 180 controls the overall operation of the terminal device 100 by controlling the wireless communication unit 110, the microphone 120, the camera module unit 130, the output unit 150, and the memory unit 160, respectively. do. For example, it performs related control and processing for voice calls, data communication, video calls, and the like.

The channel scan unit 181 constituting the control unit 180 scans a channel of an access point that can wirelessly connect to the short-range communication unit 112 of the wireless communication unit 110, and memory unit for channel history information about the scanned channel It is stored in the channel information storage unit 162 of (160).

The wireless access control unit 182 determines whether the channel state of the wirelessly accessed access point satisfies the handoff condition, and if the handoff condition is satisfied, some channels based on channel history information of the channel information storage unit 162 among all channels The short-range communication unit 112 of the wireless communication unit 110 is controlled to process a handoff for wireless access to an access point supporting a wireless LAN service through one channel among some channels according to a result of a channel scan targeting.

Also, the wireless access control unit 182 preferentially attempts a handoff according to the result of the channel scan performed on some channels included in the channel history information of the channel information storage unit 162, and the attempted handoff is If it fails, a handoff may be attempted suboptimally according to the result of the channel scan performed on the remaining channels except for some channels.

In addition, the wireless access control unit 182 preferentially attempts a handoff according to the result of the channel scan performed on the currently used channel, and if the attempted handoff fails, part of the channel information storage unit 162 Depending on the result of the channel scan targeting the channel, handoff may be attempted suboptimally.

2 is a flowchart illustrating a short-range wireless access handoff method according to an embodiment of the present invention.

As shown in this, the short-range wireless access handoff method according to an embodiment of the present invention includes the step (S201) of scanning the entire channel for wireless access with an access point supporting a wireless LAN service.

In addition, the method further includes storing channel description information including information on a serviceable channel among all channels (S203).

Wireless access to an access point supporting a wireless LAN service through one of the serviceable channels (S205) is further included.

In addition, the method further includes determining whether the channel state of the wirelessly connected access point satisfies the handoff condition (S207).

Here, if it is determined that the handoff condition is satisfied, further comprising steps S209 and S211 of performing a channel scan on some channels based on channel description information among all channels.

And, if there is an access point that satisfies the handoff condition according to the result of the channel scan for some channels, performing a handoff to wirelessly access the access point supporting the wireless LAN service through one channel of some channels. (S213, S217).

In addition, if there is no access point that satisfies the handoff condition according to the result of the channel scan for some channels, the access point that satisfies the handoff condition according to the result of the channel scan for the remaining channels except for some channels Step of performing a handoff to wirelessly access (S213, S215).

Hereinafter, a short-range wireless access handoff method and a wireless LAN service process performed by a terminal device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

First, the channel scan unit 181 of the control unit 180 constituting the terminal device 100 controls the short-range communication unit 112 of the wireless communication unit 110 to wirelessly access an access point disposed in the wireless LAN zone. The channel is scanned (S201).

Subsequently, the channel scan unit 181 stores channel history information including information on a serviceable channel according to the channel scan result in the channel information storage unit 162 of the memory unit 160 (S203).

The wireless access control unit 182 of the control unit 180 selects any one of the channels scanned by the channel scan unit 181, and controls the short-range communication unit 112 to wirelessly access the access point through the selected channel. Here, the wireless access control unit 182 may select the optimal access point and channel in consideration of RSSI strength of the scanned channels.

Then, the short-range communication unit 112 wirelessly accesses the access point through the selected channel under the control of the wireless access control unit 182, and is assigned an IP address for the wireless LAN service from the wirelessly accessed access point (S205).

Then, the access point periodically broadcasts the beacon message, and the short-range communication unit 112 periodically receives the beacon message from the access point.

In this way, when the short-range communication unit 112 wirelessly connects to the access point disposed in the wireless LAN zone, the terminal device 100 may use the wireless LAN service through the wirelessly accessed access point.

Meanwhile, while using the wireless LAN service, the wireless access control unit 182 determines whether the channel state of the wirelessly accessed access point satisfies the handoff condition. For example, if the RSSI strength of the currently connected channel is compared to a preset reference value, and if the RSSI strength of the corresponding channel is smaller than the reference value, it may be determined that the wireless environment is unstable and thus satisfies a handoff condition for handoff. (S207).

As described above, when the handoff is determined by the wireless access control unit 182, the channel scan unit 181 must select the channel for handoff again, and in the prior art, the channel targets all access points disposed in the wireless LAN zone. Was scanned again.

However, in the present invention, the channel scan unit 181 checks channel history information previously stored in the channel information storage unit 162 of the memory unit 160 (S209), and targets all access points disposed in the wireless LAN zone. Instead of re-scanning the channel, the channel is re-scanned for some channels included in the pre-stored channel history information (S211). At this time, the channel history information for the re-scanned channel may be stored in the channel information storage unit 162 so that it can be used in subsequent channel scans.

Next, the wireless access control unit 182 of the control unit 180 determines whether there is an access point that satisfies a handoff condition, for example, a condition in which the strength of the RSSI is greater than or equal to a predetermined criterion among the channels scanned again by the channel scan unit 181. (S213).

Here, the wireless access control unit 182 selects a corresponding channel when an access point that satisfies the handoff condition exists, and allows the short-range communication unit 112 to handoff through the selected channel, that is, wirelessly accesses the access point through the corresponding channel. Control. Here, the wireless access control unit 182 may select the optimal access point and channel in consideration of RSSI strength of the re-scanned channels.

Then, the short-range communication unit 112 performs a handoff for wireless access to the access point through the selected channel again under the control of the wireless access control unit 182, and can continuously use the wireless LAN service through the wireless access point. Yes (S217).

Here, there are several access points in the vicinity, and in the case of a dual band supporting both 2.4 GHz and 5 GHz, there are 13 channels from channels 1 to 13 for 2.4 GHz, and 36 channels for 5 GHz. There are 19 channels from channel 161. When the channel scan time required to scan one channel is τ, and the number of channels stored in step S203 is α, the access time according to the handoff processing according to the prior art takes time τ×32. However, according to the present invention, the connection time according to the handoff process is as long as τ×α.

For example, if the channel scan time (τ) required to scan one channel is 200 msec and the number of channels α stored in step S203 is eight, the present invention is compared with the prior art according to handoff processing. The connection time is reduced by 4.8 sec as shown in Equation 1 below.

On the other hand, if there is no access point that satisfies the handoff condition among the channels scanned in step S213, a partial channel scan is performed again for the remaining channels that are not included in the channel history information stored in step S203 among all channels, and then scanned again. It is possible to perform a handoff to change the channel to any one of the channels. That is, a handoff is preferentially attempted according to a result of a channel scan performed on some channels included in the channel history information of the channel information storage unit 162, and if the attempted handoff fails, the rest of the channels are excluded. The handoff is attempted suboptimally according to the result of the channel scan performed on the channel (S215, S217).

In addition, a handoff is preferentially attempted according to the result of a channel scan performed on a currently used channel, and if the attempted handoff fails, some channels included in the channel history information of the channel information storage unit 162 Depending on the result of the channel scan targeting, a handoff may be attempted suboptimally.

For example, based on channel history information previously stored by the primary channel scan, a secondary channel scan is performed for only the currently used channel, and if there is an access point suitable for wireless access among the secondary scanned channels Handoff is performed by switching to an access point. However, if an access point suitable for the same channel does not exist, a third channel scan is performed for other channels based on pre-stored channel history information, and a wireless access is switched to an access point suitable for wireless access among the third scanned channels. Is to perform a handoff.

As described so far, when performing handoff, handoff may be performed through one channel of some channels according to a result of a channel scan targeting some channels based on channel history information for a service channel previously stored. have.

Therefore, since all channels of all bands are not scanned, unnecessary channel scan time is saved, and as a result, connection can be quickly performed during handoff.

In addition, since the user can make a faster connection than the existing whenever the handoff or handoff conditions are satisfied, smooth WLAN communication can be used.

Combinations of each block in the block diagrams and each step of the flowcharts attached to this specification may be performed by computer program instructions. These computer program instructions may be mounted on a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, so that instructions executed through a processor of a computer or other programmable data processing equipment may be used in each block or flowchart of the block diagram. In each step, means are created to perform the functions described. These computer program instructions can also be stored in computer readable or computer readable memory that can be oriented to a computer or other programmable data processing equipment to implement a function in a particular way, so that computer readable or computer readable memory The instructions stored in it are also possible to produce an article of manufacture containing instructions means for performing the functions described in each step of each block or flowchart of the block diagram. Computer program instructions can also be mounted on a computer or other programmable data processing equipment, so a series of operational steps are performed on a computer or other programmable data processing equipment to create a process that is executed by the computer to generate a computer or other programmable data. It is also possible for instructions to perform processing equipment to provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

Further, each block or each step can represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function(s). It should also be noted that in some alternative embodiments it is possible that the functions mentioned in blocks or steps occur out of order. For example, two blocks or steps shown in succession may in fact be executed substantially simultaneously, or it is also possible that the blocks or steps are sometimes performed in reverse order depending on the corresponding function.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims below, and all technical thoughts within the equivalent range should be interpreted as being included in the scope of the present invention.

According to an embodiment of the present invention, when changing a channel of a short-range wireless connection for a wireless LAN service, all channels in all bands are not scanned, thereby saving unnecessary channel scan time, and as a result, the connection can be quickly performed during handoff. Can be. In addition, since the user can make a faster connection than the existing whenever the handoff or handoff conditions are satisfied, smooth WLAN communication can be used.

The present invention can be used for various terminal devices capable of communication, such as a smart phone, a tablet computer, a notebook computer, a PDA, etc. that can access a wireless LAN using short-range communication such as Wi-Fi.

100: terminal device 110: wireless communication unit
112: short-range communication unit 120: microphone
130: camera module unit 140: user input unit
150: output unit 160: memory unit
161: operating system program 162: channel information storage unit
170: interface unit 180: control unit
181: channel scanning unit 182: wireless access control unit

Claims (6)

First scanning a channel for wireless access with an access point supporting a wireless LAN service;
Storing channel description information including information on a serviceable channel according to the first scan result;
Wirelessly accessing an access point supporting the WLAN service through one of the serviceable channels;
Determining whether a channel state of the wirelessly connected access point satisfies a handoff condition;
If it is determined that the handoff condition is satisfied, performing a secondary scan for only the currently used channel based on the channel history information;
First attempting a handoff to wirelessly access the changed access point according to the result of the second scan;
If the first attempt fails, performing a third scan on some channels based on the channel history information; And
Secondly attempting a handoff to wirelessly access the changed access point through one of the channels according to the result of the third scan for the some channels.
Short-range wireless access handoff method comprising a. According to claim 1,
If the second attempted handoff is unsuccessful, attempting a handoff suboptimally according to the result of the channel scan performed on the remaining channels except for some of the channels
Short-range wireless access handoff method, characterized in that. delete A wireless communication unit wirelessly accessing an access point supporting a wireless LAN service through a serviceable channel among all channels;
A channel scanning unit that scans a channel for wireless access with an access point supporting the WLAN service;
A channel information storage unit in which channel history information including information on a serviceable channel among all channels is stored; And
It includes a wireless access control,
The wireless connection control unit,
When the channel state of the wirelessly accessed access point satisfies the handoff condition, the channel scan unit is controlled to perform a secondary scan for only the currently used channel based on the channel history information, and changed according to the result of the secondary scan. Control the wireless communication unit to first attempt a handoff for wireless access to an access point, and scan the channel to perform a third channel scan on some channels based on the channel description information when the first attempt fails The wireless is controlled to secondaryly attempt a handoff for wireless access to an access point supporting the WLAN service changed through one of the channels according to the result of the third channel scan for the some channels. To control the communication department
Terminal device. The method of claim 4,
The wireless connection control unit,
If the second attempted handoff is unsuccessful, attempting a handoff suboptimally according to the result of the channel scan performed on the remaining channels except for some of the channels
Terminal device characterized in that. delete

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